Aircraft galley monument structure

ABSTRACT

An improved monument structure combining an integrated construction system with carbon fiber reinforced composites to form an exoskeleton chassis that significantly reduces the build times, manufacturing skill level requirements, post processing activities, and overall weight of a given aircraft monument.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a continuation application based on U.S. application Ser. No.13/850,781, filed Mar. 26, 2013, which claims priority from U.S.Application No. 61/616,904, filed Mar. 28, 2012, which are incorporatedherein by reference in their entirety.

BACKGROUND

Commercial passenger carrying airplanes commonly have storage orcompartment structures (frequently referred to by the generic name“monuments”) installed on the aircraft. These structures are used in avariety of ways, such as storage of clothing and other passengerbelongings, electronic entertainment centers, sleeping quarters for theofficers and cabin crew, purser work stations, bar units, lavatories,and galleys used to provide in-flight catering meal service to thepassengers. Traditionally, these monuments have been manufactured usingmulti-layered lightweight assemblies known as “sandwich panels” ofNomex® or Kevlar® cores, with resin pre impregnated fiberglass skinsforming the surface. Other types of composite panels are manufacturedwith foam, thermo-plastic or metallic core materials and with plastic ormetallic outer skins. Aircraft monuments may alternatively beconstructed entirely from flat sheet materials that are pre manufacturedin a process using a multi-layer temperature controlled press, and/orfrom molds using an autoclave to provide both temperature and pressurefor curing of the panel, part or section.

Following manufacture, these parts or sections have to undergoadditional “pre or post processing” where they may be trimmed, cutand/or formed into the parts necessary to construct the monument. Theywill also commonly undergo secondary operations to have fixing pointsand/or locating holes installed in the form of “inserts” or “bobbins.”In the case of the former, they provide a means of attaching items tothe panel, and rely on the injection of an adhesive around the fixing toform a plug that resists being pulled out through the skin when a loador force is applied to it. In the case of the latter, a through hole isprovided for fixings that would otherwise damage the panel.

Items attached to the panels include wiring looms and electricalcomponents, plumbing hoses, pipes and components, ventilation and airextraction duct, hose and component mountings, décor panels, hinges,back stops, galley insert equipment interfaces, access panels, ducts,sliders and draw runners, electronic entertainment devices, grilles, andgeneral equipment retainers.

After the preparatory stages are complete, the monument is constructedby assembling the various parts, either by bonding the flat panelstogether to form a rigid structure with viscous liquid adhesives, or bycombining the flat panels with pre manufactured (e.g. pre cured) moldedparts to form the basic structure. These molded sections or flat panelsub-assemblies may also remain as removable (i.e. bolt on/bolt offparts). Likewise, adhesive bonded flat panels forming sub-assemblies ormodules may be bolted together to form the complete structure.

Basic construction in all cases involves a post composite panelmanufacturing process that relies on bonding using liquid adhesives forthe panels forming the structure itself, the fixing points, throughholes and mountings and/or the sub-assemblies, modules and moldingsthemselves. Further, secondary operations attaching various loosemetallic and non-metallic parts to the basic structure, together withelectrical, water and air systems are then undertaken. These separateprocesses add significantly to the cost and construction time, andrequire a high level of expert knowledge and operator skill.

Another issue with the current monument construction is the need forreinforcement. To reinforce a given monument structure, “C,” “U,” “H,”“F” and right angle as well as other shapes of section aluminumextrusions are commonly bonded to the edges of the panels for stiffness.Where local re-enforcement of the structure is required (for loadbearing purposes), flat sheets of aluminum, typically 1/32″ to ⅛″ thick,are bonded to the panel to transfer the effects of localized stress toportions of the structure with higher load bearing capabilities. Thistype of additional localized reinforcement is commonly called a“doubler.” This practice adds significant weight to the Monument andrequires another manufacturing process, adding the cost.

SUMMARY OF THE INVENTION

The present invention is an improved monument structure combining anintegrated construction system with carbon fiber reinforced compositesto form an exoskeletal chassis that significantly reduces the buildtimes, manufacturing skill level requirements, post processingactivities, and overall weight of a given aircraft monument. Newmonument designs may be analyzed using finite element analysis todetermine the maximum load that will be imposed on the improvedstructure, and then all local reinforcement requirements will beincorporated into the integrated structure as determined by themonument's worst case loading determination.

The construction of the monument of the present invention calls fordesigning the lay-up of a composite panel sandwich to include integrallocalized reinforcement, capable of handling the stress loads imposed onthe structure without the need for additional supplementary metallicreinforcement. All fixing points (which include both floating and fixedpotted inserts), through holes, brackets, back stops for cart thatprevent rearward movement, wear strip bases (rub and bump strips)trolley wheel guides, GAIN interface points, ducts, electrical routingchannels and other secondary process items, are incorporated in theprimary manufacturing process.

The primary manufacturing process consists of a modular, reversedmolding system utilizing carbon fiber reinforced composite preimpregnated skins (referred to as CFRCs) with or without a corestructure, and localized reinforcement of unidirectional carbon fiber(referred to as UD fiber) that are applicable to the structuralrequirements and loadings of the particular monument. Where applicable,previously manufactured I and H beams are incorporated into thestructure to provide high strength reinforcement. The molds may or maynot be modular in construction, depending on the type of monument beingconstructed, and will have a specific construction applicable to theirintended function.

Other features and advantages of the present invention will become moreapparent from the following detailed description of the preferredembodiments in conjunction with the accompanying drawings, whichillustrate, by way of example, the operation of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevated, perspective view of a first embodiment of themonument structure of the present invention;

FIG. 2 is a partially exploded, elevated, perspective view of theembodiment of FIG. 1;

FIG. 3 is a perspective view of the above work deck sub-assembly of theembodiment of FIG. 1;

FIG. 3a is an enlarged, perspective view of the way in which thecompartments of the above work deck are formed;

FIG. 3b is a cross-sectional view of an intersection of the panels inthe sub-assemblies of the present invention;

FIG. 4 is a perspective view of the below work deck sub-assembly of theembodiment of FIG. 1;

FIG. 4a is a cross-sectional view of the mating of the above work deckand below work deck sub-assemblies;

FIG. 5 is an enlarged, perspective view of the bump strip carrier forthe below work deck sub-assembly of FIG. 4;

FIG. 6 is an enlarged, perspective view of an integrated floorattachment device of the sub-assembly of FIG. 4;

FIG. 7 is a perspective, front view of the rear service wall of themonument structure; and

FIG. 8 is an enlarged, perspective view of a composite roof attachment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate a first preferred composite aircraft monumentin the form of a refrigerated center line galley 10 that comprises threemain chassis sub-assemblies, a below work deck area (BWD) 12, an abovework deck area (AWD) 14, and a removable, one piece rear service wall(RSW) 16. The AWD section 14 provides compartments 18 as required forgalley inserts, or GAINs, such as coolers, ovens, coffee brewers, andthe like to be installed. The AWD section 14 compartments 18 alsoprovide space for meal boxes or standard units (SUs), and miscellaneousstorage in the same way, together with compartment door hinge and latchlocations, if so required. On top of the above work deck area 14 is apair of composite ceiling mounts 20 for attaching the monument 10 fromabove to the ceiling or supporting structure of the airframe.

The compartments 18 of the above work deck 14 are defined by panels 22as shown in FIG. 3, that is formed of previously manufactured flatCFRC-faced panels integrated into the structure using slots 28 at theintersection of the horizontal shelves 24 and the vertical walls 26 (SeeFIG. 3a ). The shelves 24 and walls 26 are formed using a wet layprocess where layers 30 of material are placed in a mold in over a wetlay 32, and the walls 26 and shelves 24 are then integrated into theassembly using additional UD reinforcing plies 34 (see FIG. 3b ). Whenformed in this manner, the panels need no additional secondarystiffening, and separate metallic edge members are not required,although the edges of the panel may be sealed with a lightweight plasticextrusion. The edges may also be covered with overlapped panel skinplies 38. The “B” surface 30, i.e. the finished molded surface oppositethe usual orientation of the lay-up, of the AWD molding preferablyeither provides the upper section of the air ducting for a chiller inthe work deck (“CIWD”) air chiller fed system, or provides for a CIWDline replacement unit (“LRU”) chiller module. Non-chilled galleys thatmay not have this provision for ductwork may instead have a structurefor other items such as sliding tables. In a preferred embodiment, thewhole AWD section 14 is cured as a single and complete integratedstructural sub-assembly.

On the upper surface 40 of the above work deck area 14 is a pair ofhorizontal channels 42 that can be used to adjustably position themonument 10 within the aircraft. Roof attachments 20 (see FIG. 8) isformed of a high strength composite and have orthogonal plates 21, 23,where plate 21 extends below a lower surface 23 a such that plate 21 canslide within its channel 42 and be clamped or fastened in the desiredlocation. The plate 23 then rests on the upper surface 40 of the abovework deck 14 to stabilize the attachment. The roof attachment 20 caninclude a lug 25 that can be used to bolt, rivet, or otherwise securethe monument 10 to the upper airframe structure.

The BWD section 12 provides accommodation in the form of two largecabinets 50 for meal service carts or trolleys, storage compartments,waste container areas, trash compactor location, galley waste disposalunits (GWDU) and/or miscellaneous stowage areas. Further, the below workdeck section incorporates fixing and locating points, includingintegrated aircraft floor attachment devices 70 (see FIG. 6), back stops80, cart dividers (T dividers) 85, and rub and bump strip bases 90.Divisions between the compartments are formed during the wet lay processor integrated into the assembly using additional UD reinforcing plies,as discussed above with respect to FIG. 3. FIG. 5 shows a view of therub and bump strip 90, along with the back stop 80 to prevent thebeverage cart (not shown) from extending too far into the cabinets 50.

FIG. 6 illustrates an integrated floor attachment device 70 incorporatedinto the walls 210 of the below work deck section 12. The floorattachment device 70 comprises two horseshoe shaped plates 120 having anouter radius along the perimeter and an inner radius along the inneredge. The two plates 120 are joined together along the inner radius by arigid panel 130, such that there is an arcuate gap between the twoplates 120, and between the rigid panel 130 and the outer radius of thetwo plates 120. The connection of the two plates 120 to the rigid panel130, such as by welding for example, is sufficient to transfer loadsfrom the panel 130 to the plates 120.

At the base of the attachment device 70 are a pair of lugs 140 includinga vertical channel 150 sized to receive a fastener (not shown). The lugs140 are preferably positioned such that no more than half of the lug 140is outside of the envelope of the two plates 120. The two lugs 140 areformed from a common block, that also connects to the rigid panel 130.The bottom edge of the plates 120 coincide with a bottom edge of thelugs 140 such that the attachment device 70 lays flush with a floor ofthe aircraft. Sandwiched between the monument walls is a composite panelcore material 220 that forms the interior of the wall structure. At thebase of the wall, between the panels 210, is the floor attachment device70 that is used to mount the wall to the floor of the aircraft. A spaceabove the cylindrical lugs 140 can be used to insert and remove thefasteners, and the arch shape of the fitting contributes to the overallstrength of the fitting.

In a preferred embodiment, the attachment device 70 is integrated in thewall structure of the monument 10 during the primary build phase,eliminating the need for a secondary operation and greatly improving thecomponent strength and the ability of the structure to handle bothstatic and dynamic loads. This is particularly important in a vehiclesuch as an aircraft, which is subject to dynamic loads on a consistentbasis. The lugs 140 create a small offset that allow the monumentstructure to have a greater proportion of standardized parts whilereducing the weight of the component as well as the footprint of themonument. In a non-metallic form, such as a composite or hardenedplastic, the fitting 70 can be mass produced, very light, and resistantto corrosion.

As the panels of the above work deck 14 and below work deck 12 need noadditional secondary stiffening, separate metallic edge members are notrequired; however, the edges of the panel may be sealed with alightweight plastic extrusion 137 or use overlapped panel skin plies(FIG. 4a ). The mating surface of the BWD's molding either provides thelower section of the air ducting for a CIWD air chiller fed system orprovides for a CIWD LRU chiller module. Further, the whole BWD section12 is preferably cured as a single and complete integrated structuralsub assembly. Note the AWD 14 and BWD 12 sub assemblies have theprovision of male and female attachment points to allow structuralconnection of the two halves. The alignment of the two matingsub-assemblies 12,14 share a common through-hole 131 that can be used tosecure the two components. When the two mating surfaces are boltedtogether, a gap 133 is formed between the surfaces that can promotecooling or venting.

FIG. 7 illustrates the rear service wall 16, which preferably carriesthe majority of the galley electrical and plumbing service provisions.The RSW also provides the integrated chilled air ducting system (forboth the AWD 14 and BWD 12 in the case of an air chiller suppliedgalley, and BWD only in the case of a chilled liquid supplied galley),and applicable galley insert retention and location provisions. The rearservice wall 16 is also preferably cured as a single and completeintegrated structural sub assembly. Wiring and plumbing components aremounted to the RSW 16 following the curing process. The RSW sub assemblymay also have the provision of male and female attachment points toallow a structural connection to the two halves of the AWD and BWD subassemblies. In a preferred embodiment, the rear service wall 16 includesa series of air vents 171 near the bottom of the RSW, where the vents171 are located in recesses in the wall as shown in FIG. 7. The recessesextend vertically to a midpoint, where they funnel and consolidate intoa single recess that vents through the top of the RSW 16. This ventingsystem allows air to circulate over the electrical system to preventoverheating, or to cool the backs of refrigeration units or other GAINsthat require venting.

Although the above examples relate to one type of monument, i.e. agalley, the present intention is not limited in this manner and isapplicable to the use and incorporation in the construction of othercommercial aircraft monuments using the same or broadly similar methods.

The present invention is characterized in that the replacement ofconventional pre-impregnated fiber glass panel skin materials withcarbon fiber reinforced composites pre impregnated panel skin materialsare used to form a structurally competent exoskeleton chassis thatproduces significant weight savings and strength advantages. The presentinvention also results in the elimination of a high percentage of coldbridges (caused by conduction through embedded metallic fixings, edgemembers, floor fittings, etc.) that are present between the exterior andthe interior of refrigerated or chilled galley compartments, resultingin improved thermal insulation capabilities and lower cooling powerrequirements from the air or liquid chiller supplying the monument.

The present invention also leads to the elimination of a significantpercentage of aircraft monument panel secondary processing operations,consisting of the provision of load bearing attachment points, throughholes, locating points, access apertures, air ducting, reinforced beams,air craft attachment points, rub and bump strips, T dividers, backstops, etc., by integrating them into the primary molding operation.This results in a reduction in construction man hours, partialde-skilling of manufacturing processes, and significant weight savingadvantages.

The present invention allows for the integration of chilled airdistribution into the structure work deck area. Additionally, thecombination of dry panel components, specific area reinforcements andpre manufactured CFRC parts incorporated into an integrated wet layassembly lead to the formation of structural skeletal sub-assemblies. Anadvantage of the present invention is the elimination of the currentrequirement for metallic edge members for the purpose of stiffeningand/or edge sealing of structural galley composite panels, through theuse of CFRC panels with overwrapped skin or plastic capped edges. As setforth above, this provides significant cost and structure weightsavings.

Another benefit of the present invention is the elimination of the useof supplementary localized metallic reinforcements. The presentinvention utilizes additional UD carbon plies (where required) toprovide an integral integrated reinforcement solution, and results insignificant manufacturing process time, and overall structure weightsavings. The integration of major services into a single removable backpanel for monuments, where electrical, plumbing, vacuum, refrigeration,CAX or ventilation systems are required, simplifies assembly and allowsparallel flow line production.

Yet another feature of the present invention is the adoption of reversemolding to combine a wet/dry composite lay-up consisting of uncuredmaterials, pre manufactured panels and composite components, to form anintegrated primary manufacturing system. Additionally, the presentinvention's use of CFRCs significantly increases the strength of themonument for a given size while decreasing the structure weight. Also,the wet/dry molding system significantly reduces build times byintegrating many secondary assembly operations into the primarymanufacturing process.

A secondary benefit of the present invention is that the primarymanufacturing process significantly reduces the volume of metallic partsin the structure, substantially reducing the weight. This also leads tothe elimination of a significant volume of metallic cold bridges betweenthe interior and exterior of chilled or refrigerated compartments, whichreduces thermal losses and the energy required to achieve the specifiedcompartment temperature.

Various features and embodiments of the present invention have beendescribed herein, but the foregoing description is not intended to belimiting or exclusive. Rather, it would be apparent to one of ordinaryskill in the art that various modifications would be readily available,and the present invention is intended to cover all such modificationsand alternative embodiments.

I claim:
 1. A monument for an aircraft, comprising an above work decksubassembly, a below work deck subassembly, and a rear service wallsubassembly, wherein the above work deck subassembly and below work decksubassembly are each manufactured and cured as an integrated structuralsubassembly of carbon fiber reinforced composites (CFRC) pre-impregnatedpanel skins; and wherein an array of compartments are formed in theabove work deck using a wet lay process having layers of a materialplaced in a mold over a wet lay, and then the compartments arereinforced with unidirectional carbon fiber reinforcing plies.
 2. Themonument for an aircraft of claim 1, wherein the monument is arefrigerated centerline galley.
 3. The monument for an aircraft of claim2, wherein the array of compartments are sized to house galley inserts(GAINs) in the galley.
 4. The monument for an aircraft of claim 1,wherein a finished molded surface of an above work deck subassemblymolding provides an upper section of an air ducting for a chiller in theabove work deck subassembly.
 5. The monument for an aircraft of claim 1,further comprising a pair of channels on an upper surface of the abovework deck that each receive a ceiling mount for mounting the monument toan upper portion of an airframe of the aircraft.
 6. The monument for anaircraft of claim 1, wherein the below work deck subassembly includesfloor fixtures embedded in the below work deck subassembly during amanufacturing process.
 7. The monument for an aircraft of claim 1,wherein fixing points are integrated into the monument using a wet layprocess.
 8. The monument for an aircraft of claim 1, wherein the abovework deck subassembly and the below work deck subassembly are sealedwith a plastic extrusion.
 9. The monument for an aircraft of claim 1,wherein the rear service wall subassembly includes vents and recessesthat cooperate to vent air through the monument.